To illustrate parallel construction, consider the clear, parallel phrasing: 'The treatment group had a mean of $23.40$ ($SD = 9.33$), while the control group had a mean of $20.87$ ($SD = 8.45$).' This consistent formatting allows readers to easily compare the means and standard deviations. In contrast, a nonparallel and confusing alternative would be: 'The treatment group had a mean of $23.40$ ($SD = 9.33$), while $20.87$ was the mean of the control group, which had a standard deviation of $8.45$.'